in vivo vs biology

in vivo is not a noun while biology is a noun.

Word	Noun	Adjective	Verb	Adverb
in vivo	No	Yes	No	Yes
biology	Yes	No	No	No

in vivo (noun)	biology (noun)
	the science that studies living organisms
	all the plant and animal life of a particular region
	characteristic life processes and phenomena of living organisms

in vivo (adjective)	biology (adjective)
of a biological process occurring within a living organism

in vivo (adverb)	biology (adverb)
in the living organism